This invention relates to the field of marine remotely operated vehicles (ROV) and the connection between the surface ship and the ROV, referred to as an umbilical. The umbilical usually has a structural connection to the surface ship, in the form of a cable, and additional lines providing electrical power, video feed, command and control, and other functions, as needed.
Remotely operated vehicles (ROV) are unmanned robotic submarines that operate at ocean depths up to 10,000 feet. ROVs are tethered to the mother ship by an umbilical for recovery and other functions. As the capabilities of ROVs increase, the size, horsepower and weight has increased which requires an umbilical of greater strength and weight. For example, 10,000 feet of umbilical will have an in water weight of 20,000 pounds. The umbilical weight is a problem for the operation of the ROV as it restricts mobility. To overcome this restricted mobility, the weight of the umbilical has been reduced by the use of floatation gear mounted along the umbilical.
High density foam floats clamped onto the umbilical have been used to compensate for the umbilical weight. The floats have been manually clamped onto the line at intervals of about 40 feet for the first 500 feet as the ROV is deployed to give the ROV a 500 feet radius of operation free of weight restriction. However, this process is very dangerous since the operators must reach over the side of the ship and, simultaneously, have control of the umbilical and manipulate a 60 pound air weight float to clamp it about the umbilical, as the umbilical is fed out. When the mission is completed and the ROV is recovered, these floats must be removed in the same manner before the umbilical is wound on the winch drum. In addition to the danger inherent in this process, there is usually no secure place to store the floats on the deck in close proximity to the operation. The clutter of floats fouls the deck and adds to the danger of the operation.
Recently, a continuous float system has been developed, such as shown in xe2x80x9cInternational Ocean Systems Magazine,xe2x80x9d Vol. 4, No. 4, July/August 2000, which has cylindrical interlocking float segments that permit bending of the umbilical. The segments may be installed directly on the umbilical. Because of the cylindrical size of the segments the bend radius is approximately 1000 mm. The float segments may each be approximately 10 inches in diameter and about 12 inches long. The use of such a system eliminates the dangerous over the side work of the earlier systems.
However, the standard sheaves used to guide the umbilical will not accommodate this newer system of large diameter cylindrical floats. Further, winding the newer floats onto a winch drum damages the float segments. To avoid these problems, an umbilical with the newer floats is sometimes zig-zagged about several sheaves on the deck rather than being spooled onto a winch drum. This wastes extremely valuable deck space.
What the prior art lacks is an automated method for deployment and recovery of the umbilical, with the floats attached, by winding and unwinding from a winch drum.
This invention teaches a system and a method for its use wherein during recovery of marine ROVs, an umbilical which has foam floatation segments that may be damaged by wrapping about the drum, are safely wrapped thereon. A flexible belt, which may be segmented or in the form of a plurality of links, is provided which is inserted between the wrapped portion of the umbilical and the floatation segments to prevent damage to the floatation segments during storage upon the drum.
Accordingly, it is an objective of the instant invention to teach a method of deployment and recovery of a float equipped ROV umbilical about a winch drum.
It is a further objective of the instant invention to teach an apparatus for preventing damage to the floatation segments during deployment and recovery of a ROV umbilical.
It is yet another objective of the instant invention to teach a segmented or linked belt placed between spooled umbilical on a winch drum and floats being wound on the drum.
Other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.